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- From: ralf+@cs.cmu.edu (Ralf Brown)
- Newsgroups: comp.os.msdos.programmer,comp.os.msdos.misc
- Subject: Re: Why ms-dos is non reentrant
- Message-ID: <BtzE9H.53G.2@cs.cmu.edu>
- Date: 3 Sep 92 02:44:03 GMT
- Article-I.D.: cs.BtzE9H.53G.2
- References: <bws.35@ccs.carleton.ca> <1992Sep1.160133.19060@mits.mdata.fi> <1992Sep2.065315.19027@zooid.guild.org>
- Sender: news@cs.cmu.edu (Usenet News System)
- Organization: School of Computer Science, Carnegie Mellon
- Lines: 27
- Nntp-Posting-Host: b.gp.cs.cmu.edu
-
- In article <1992Sep2.065315.19027@zooid.guild.org> ross@zooid.guild.org (Ross Ridge) writes:
- }kennu@mits.mdata.fi (Kenneth Falck) writes:
- }>So, the question remains, why don't the Microsoft programmers bang
- }>their brains together and rewrite MSDOS to be fully re-entrant and
- }>all the routines to use dynamic memory allocation instead of static?
- }
- }Well the reasons why this wasn't done for MS-DOS 5 and earlier releases
- }is fairly straight forward:
-
- Where have you been? It's been done already.... MSDOS 4.00 was multitasking,
- but practically nobody ever got to see it. (Note: this was a version that
- came between 3.2 and 3.3; the mass-market MS equivalent to PC-DOS 4.0x was
- MSDOS 4.01). And if you're open to buying from a Microsoft competitor, you
- can get Digital Research's DR Multiuser DOS (former versions were called
- Concurrent PC-DOS, Concurrent DOS, and Concurrent DOS/XM).
-
- MSDOS 4.00 allowed one foreground and up to 30 background tasks (limited by
- conventional memory), with interprocess communications, semaphores,
- scheduling, etc. And it supported asynchronous device drivers, where the
- split into strategy and interrupt routines actually meant something.
-
-
- --
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